This invention relates to recording and reproducing apparatus and, in particular, to such apparatus wherein an original speech signal can be replaced by a further speech signal to thereby perform the so-called voice-changing function.
Sound reproduction apparatus, known as a "voice changer," is known whereby prerecorded signals, such as stereophonic music signals, are processed to replace a particular prerecorded signal with a further signal.
This apparatus finds application where speech signals, such as signals corresponding to a vocal musical performance, are replaced by further speech signals. In particular, if the prerecorded stereophonic signals include stereo signal components corresponding to musical sounds generated by musical instruments, such as an orchestra, and voice signals corresponding to the spoken lyrics of a song, as sung by a performer, the voice changer apparatus permits an operator thereof to substitute his singing for the prerecorded singing while processing the stereo signal components. Hence, the prerecorded instrumental sounds, as by the orchestra, are processed and can be used to accompany the vocal utterances of the operator.
The ability to replace a prerecorded vocal performance with the singing of an operator has resulted in the use of such voice changer apparatus as a teaching instrument. Voice training is readily obtained, and the apparatus can be adapted to derive an improvement in singing technique.
However, it has been found that beneficial use of voice changer apparatus is attained if the vocal performance by the operator can be compared with the original, prerecorded performance. Stated otherwise, it is desirable for one, such as an operator, to be able to simultaneously listen to the original vocal performance, as prerecorded, with the vocal performance corresponding to the operator's singing. Unfortunately, the typical prior art voice changer apparatus does not have the capability of reproducing simultaneously the original performance and the substitute performance so that an audible comparison can be made. Hence, the prior art apparatus cannot be fully exploited to achieve the most favorable results.